Harvard University
Eyes on the Sky, Feet on the Ground: The Earth's Rotation
Plenty of cool activities about the Earth's rotation can be found here, such as tracing shadows, observing shadows during different times of the day, and tracking the sun's path in the sky to understand the rotation of the earth.
NASA
Nasa: Imagine the Universe: Speed of Earth's Rotation
Presents an informative answer to the question "What is the speed of the turning of the Earth?"
NASA
Nasa: Eclipse Predictions and Earth's Rotations
An insightful website from NASA that presents a series of different questions about the rotation of the Earth.